Prime & Composite
Is 29 prime or composite
29 is prime. It has no positive divisors other than 1 and 29
Evaluate: 7+3×57+3×5
Multiply first: 3×5=153×5=15. Then add: 7+15=227+15=22
Maya has 45 stickers. She gives 12 to her friend. How many stickers does she have left?
45−12=33 stickers
136×4
136×4=544136×4=544
Fill the next number and what is the pattern: 2, 4, 6, 8, ___
Answer: 10 (pattern: add 2)
List all the prime numbers between 10 and 30
11, 13, 17, 19, 23, 29
Evaluate: (8+2)×6−4(8+2)×6−4
Parentheses first: (8+2)=10(8+2)=10. Multiply: 10×6=6010×6=60. Subtract: 60−4=5660−4=56
A box holds 24 pencils. If a teacher has 6 boxes, how many pencils does she have in total
24×6=144 pencils
237×15
Work: 237×15=237×(10+5)=2370+1185=3555237×15=237×(10+5)=2370+1185=3555.
Answer: 3555
Fill the next two numbers and what is the pattern: 5, 10, 15, ___, ___
Answer: 20, 25 (pattern: add 5)
Explain whether 1 is prime, composite, or neither
Neither. 1 has exactly one positive divisor (1), so it is not prime (needs exactly two distinct positive divisors) and not composite (would have more than two)
6÷2×3
Start from left to right:
6÷2=3
Then, multiply by 3:
3×3=9
A store sold 128 apples on Monday and three times that many on Tuesday. How many apples were sold on both days combined
Work: Tuesday = 3×128=3843×128=384. Total = 128+384=512128+384=512.
Answer: 512 apples
Multiply: 1,204×371,204×37
Work (standard):
1,204×30=36,1201,204×30=36,120
1,204×7=8,4281,204×7=8,428
Add: 36,120+8,428=44,54836,120+8,428=44,548.
Answer: 44,548
The pattern multiplies by 3 each step: 2, 6, 18, ___, ___
Answer: 54, 162
Is 221 prime or composite
221 is composite. Quick test: try small prime divisors. 221 ÷ 13 = 17, so 221 = 13 × 17
5×(3+2)
First, solve what's inside the parentheses:
3+2=5
Then, multiply by 5:
5×5=25
Joshua has a total of 168 sodas. Using the sodas, he will fill empty boxes that hold 12 sodas. What is the greatest number of boxes that Joshua can fill completely?
14 Boxes and 168 Cans
A factory makes 2,345 toys each day. How many toys will it make in 30 days? Show multiplication and final answer.
Work: 2,345×30=2,345×(3×10)=(2,345×3)×102,345×30=2,345×(3×10)=(2,345×3)×10
2,345×3=7,0352,345×3=7,035
Multiply by 10: 7,035×10=70,3507,035×10=70,350.
Answer: 70,350 toys.
What is the rule for this pattern and the next number: 3, 6, 12, 24, ___
Rule: multiply by 2 each time (or double). Next number: 48
Find the prime factorization of 360. Show your steps.
360 = 36 × 10 = (6 × 6) × (2 × 5) = (2 × 3) × (2 × 3) × 2 × 5. Collect factors: 360 = 2^3 × 3^2 × 5
10−3+5
Start from left to right:
10−3=7
Then, add 5:
7+5=12
On Saturday 132,654 guests visited Busch Gardens. On Sunday Busch Gardens had 129,783 guests visit. How many more guests visited Busch Gardens on Saturday
2,871 guests
422 x 97
422 × 7
7 × 2 = 14 (write 4, carry 1)
7 × 2 = 14 + 1 = 15 (write 5, carry 1)
7 × 4 = 28 + 1 = 29
Result: 2,954
Create a rule and give the next two numbers for this pattern: 7, 14, 28, 56, ___, ___
Rule: multiply by 2 (double each term). Next two numbers: 112, 224